A device for harvester-threshers has been known which maintains the upright position of the machine irrespective of the unevenness of the soil. This device senses the tilt of the body by means of two oppositely-acting liquid-filled switches which, by means of control the winding coils of a first electromagnetic valve which in its turn directs the liquid discharged by a pump towards two double action hydrostatic cylinders which bring the machine back into an upright position. The operation of bringing the machine into an upright position is achieved by the device in a selective way, in two steps, namely for small tilts, a part of the flow of the pump, by means of a second electromagnetic valve is short-circuited through a shutter at the tank. The known device has the disadvantage of only two step operation, i.e. with jerks, reduced reliability due to a large number of electric contacts in continuous action, complexity and high factory cost of the components.